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Run a Basic Python Flask Restful API

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In this tutorial we will run a basic api using flask-restful, it will only have two routes which will be a get and post method for the purpose of demonstration.

What is Flask Restful

Flask-RESTful is an extension for Flask that adds support for quickly building REST APIs. It is a lightweight abstraction that works with your existing ORM/libraries. Flask-RESTful encourages best practices with minimal setup.

If you want to see a basic Flask API post, you can follow the link below:

Installation

Install Flask and Flask Restful:

python3 -m pip install flask
python3 -m pip install flask-restful

Code

The basic code that we have, is to have two methods available (get and post):

import flask
import flask_restful

app = flask.Flask(__name__)
api = flask_restful.Api(app)

class HelloWorld(flask_restful.Resource):
    def get(self):
        return {'hello': 'world'}

    def post(self):
        json_data = request.get_json(force=True)
        firstname = json_data['firstname']
        lastname = json_data['lastname']
        return jsonify(firstname=firstname, lastname=lastname)

api.add_resource(HelloWorld, '/')

if __name__ == "__main__":
    app.run(debug=True)

Run the Server

Run the server:

python api.py

Then make a get request:

curl http://localhost:5000/

The response should be the following:

{
    "hello": "world"
}

Then make a post request:

curl -XPOST http://localhost:5000/ -d '{"firstname": "ruan", "lastname": "bekker"}'

The response should look something like this:

{
  "firstname": "ruan",
  "lastname": "bekker"
}

Integration Tests

We can setup integration tests with unittest by creating test_api.py:

import unittest
import app as api

class TestFlaskApi(unittest.TestCase):
    def setUp(self):
        self.app = api.app.test_client()

    def test_get_method(self):
        response = self.app.get("/")
        self.assertEqual(
            response.get_json(),
            {"hello": "world"},
        )

    def test_post_method(self):
        # request payload
        payload = json.dumps({
            "firstname": "ruan",
            "lastname": "bekker"
        })

        # make request
        response = self.app.post("/", data=payload, headers={"Content-Type": "application/json"})

        # assert
        self.assertEqual(str, type(response.json['lastname']))
        self.assertEqual(200, response.status_code)

    def tearDown(self):
        # delete if anything was created
        pass

if __name__ == '__main__':
    unittest.main()

Then we can run our test with:

python -m unittest discover -p test_app.py -v

Since our first test is expecting {"hello": "world"} our test will pass, and our second test we are validating that our post request returns a 200 response code and that our lastname field is of string type.

The output of our tests will show something like this:

test_get_request (test_app.TestFlaskApi) ... ok
test_post_request (test_app.TestFlaskApi) ... ok

----------------------------------------------------------------------
Ran 2 tests in 0.009s

OK

More on Flask-Restful

This was a very basic example and their documentation provides a great tutorial on how to extend from this example. This is also a great blogpost on testing rest api's.

Thank You

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